Pyridine derivatives

ABSTRACT

The disclosure relates to novel bis(pyridinium quaternary salts), a process for their manufacture, compositions containing them, and a method of preventing the growth of, or killing, bacteria by applying one of the novel pyridinium salts to a bacterially infected environment.

United States Patent 1 1 1 3,875,175

Edwards 1 Apr. 1, 1975 1 PYRIDINE DERIVATIVES 75 Inventor: Philip Neil Edwards, Macclesfield, 1 References Cited England UNITED STATES PATENTS [73] Assignee: Imperial Chemical Industries 2,929,818 3/1960 Janssen 260/295 AM Limited, London England Downes et a1. Q 3,586,686 6/1971 Braunholtz 1260/2943 R [22] Filed: Dec. 27, 1973 {21] Appl. No. 428,678 Primary E.\aminerAlbert T. Meyers Assistant ExaminerN0rman A. Drezin Related Apphcatlon Data Attorney, Agent, or Firm-Cushman, Darby & [62] Division of Scr. N0. 234,648 March 14, 1972, Pat. c h

[30] Foreign Application Priority Data [57] ABSTRACT Mar. 29. 1971 United Kingdom 8071/71 The disclosure relates to novel biswyridinium q nary salts), a process for their manufacture, composi- 53 5 Cl 2 0 295 2 0 24 R, 2 0 240 E, tions containing them, and a method of preventing the 260/240 1,260/268 H, 260/294.8 R, 260/295 growth of, or killing, bacteria y pp y one of the 3 0 295 Q 2 2955 A, 25,0/2955 1 novel pyridinium salts to a bacterially infected envi- 424/57, 424/250, 424/263, 424/266 ronment- [51] Int. Cl C07d 31/44 5 Claims, No Drawings l PYRIDINE DERIVATIVES This is a division of application Ser. No. 234,648 filed Mar, l4, 1972 now U.S. Pat. No. 3,786,058.

This invention relates to novel pyridine derivatives which possess valuable antibacterial properties and some of which are useful in dental hygiene for inhibiting the formation of dental plaque.

According to the invention there is provided a pyridine derivative of the formula:

wherein R and R. which may be the same or different, are each an alkyl, alkenyl, alkoxyalkyl,alkoxyalkoxya1 kyl, alkanoyloxyalkyl or aryloxyalkyl radical of at least 6 and not more than 14 carbon atoms, a phenyl or naphthyl radical containing 0 to 3 halogen atoms, or an alkyl radical of l to 3 carbon atoms which is substituted by a phenyl or naphthyl radical which is itself substituted by 0 to 3 halogen atoms or alkyl or alkoxy radicals of l to 6 carbon atoms; A and A which may be the same or different, are each a direct linkage or a linking group of the formula -CH CO.NH- wherein the methylene radical is joined to the pyridine nitrogen atom; (X.X represents two monoanions or a dianion; and A is a linking group selected from l.(CH-z)z 2. CH:CH

3. (CH- ),,O(CH. provided that both ns are not 0,

4. (CH ),,.N(COR)(CH wherein R is an alkyl or aryl radical of up to 10 carbon atoms. and provided that both ns are not 0,

6. CO.NHNH.CO(CH ),,,(CO),.NHNH.CO

7. -CO.NHNH.CO.Y.CO.NHNH.CO

23. (CH ),,NH.CO 24. NH.COCH=CHCO.NH 25. -NH.CO(CH OCH CO.NH

wherein n is O, 1 or 2,111 is O to 12; is 0 or 1; v is 0 or 2 to 6; z is 2 or 3; Y is a phenylene or naphthylene radical; and Z is a straightor branched-chain alkylene radical of 2 to 8 carbon atoms.

When R and R are alkyl, alkenyl, alkoxyalkyl, alkoxyalkoxyalkyl, alkanoyloxyalkyl or aryloxyalkyl radicals, they are preferably straight-chain such radicals, for example n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tetradecyl, n-undec-lO-enyl, 2-nhexyloxyethyl or 2-(2-butoxyethoxy)ethyl radicals. When R and R are phenyl or naphthyl radicals containing O to 3 halogen atoms, or are alkyl radicals of l to 3 carbon atoms substituted by a phenyl or naphthyl radical which is itself substituted by O to 3 halogen atoms or alkyl or alkoxy radicals of l to 6 carbon atoms, such halogen atoms may be, for example, chlorine or bromine atoms, and the alkyl radical of l to 3 carbon atoms may be, for example, the methyl radical, so that R and R may be, for example, 3,4- dichlorophenyl, 4-chlorobenzyl, 2,4-dichlorobenzyl or 2-naphthylmethyl radicals.

When (X.X represents two monoanions, suitable anions are, for example, halide anions, for example chloride or bromide anions, anions derived from a carboxylic acid, for example the acetate anion, or anions derived from a sulphonic acid, for example the methanesulphonate or toluene-p-sulphonate anions; and when (X.X represents a dianion, a suitable anion is, for example, the sulphate or phosphate anion.

It is to be understood that although (X'.X represents two monoanions or a dianion, the corresponding monovalent radicals or atoms are X and X and the corresponding divalent radical is (X.X Thus, for example, X and X may each be chlorine or bromine atoms, or methanesulphonyl, toluenesulphonyl or acetoxy radicals, and (XKX may be, for example, the sulphate divalent radical.

A suitable phenylene or naphthylene radical is, for example, the o-phenylene, m-phenylene, p-phenylene, 1,4-naphthylene. 1,5-naphthylene, 4-methyl-l ,2- phenylene, 2,5-dimethyl-i,4-phenylene, 2,5-dimethoxy-1,4-phenylene or 2,4,5,6-tetrachlorol,3-phenylene radical.

A suitable value for Z is, for example, the ethylene, trimethylene. hexamethylene or 2,2- diethyltrimethylene radical.

Preferred linking groups A are those numbered l, 2, 6,8,9, 11,12,14, 15, 17,18, 23, 24, 25, 26, 27, 28 and 29 in the list above, and of these, particular linking groups A are:

Preferred compounds of the invention are those wherein the radicals AR and A R are the same. and a preferred group of pyridine derivatives of the invention comprises those compounds of the formula I above wherein A and A are each a direct linkage R and R are each the same alkyl or alkenyl radical of 8 to l 1 carbon atoms (X.X represents two bromide. chloride, methanesulphonate. toluene-p-sulphonate or acetate anions. or the sulphate dianion, and A is:

A particularly preferred sub-group within the above group comprises those compounds wherein A and A are each a direct linkage. R and R'-' are each an unbranched alkyl radical of 8 to 11 carbon atoms. optionally containing a terminal double bond. (X.X represents two bromide. chloride. methanesulphonate, toluene-p-sulphonate or acetate anions. or the sulphate dianion. and A is the trimethylene or ureylene radical or a radical of the formula CO.NH. and especially those compounds wherein A is linked to the same numbered carbon atom of each pyridine ring.

Particular new pyridine derivatives of the invention are described in Examples 1 to 4. and of these individual. specially preferred derivatives are 4.4- trimethylenebis( l-n-decylpyridinium methanesulphonate), (compound 5 3,3 -ureylenebis( l-ndecylpyridinium methanesulphonate). (compound 25 3,3'-ureylenebis( l-n-decylpyridinium chloride). (compound 26). 3,3-glutaramidobis(l-n-decylpyridinium chloride) (compound 78); 3.3'-glutaramidobis( l-ndecylpyridinium methanesulphonate (compound 79 3.3'-adipamidobis(l-n-decylpyridinium methanesulphonate), (compound 30); 4 4-adipamidobis( l-ndecylpyridinium methanesulphonate (compound 82 3.3'-pimelamidobis-(l-n-decylpyridinium chloride). (compound 86): 3.3-suberamidobis( l-ndecylpyridinium chloride). (compound 87); 3.3- suberamidobis(l-n-decylpyridinium methanesulphonate (compound 88); 3.3 '-azelamidobis( l-ndecylpyridinium methanesulphonate). (compound 90 3.3'-sebacamidobis( l-n-octylpyridinium methanesulphonate), (compound 31); and 33 sebacamidobis(l-n-decylpyridinium methanesulphonate) (compound 32).

According to a further feature of the invention there is provided a process for the manufacture of the novel pyridine derivatives of the invention which comprises:

a. the quaternisation of a pyridine derivative of the formula:

with a quaternising agent or quaternising agents (R'A).X, (R A ).X or (RA)(R A ).(X .X) wherein A, A A R and R have the meanings stated above and X" X and (X*.X*) are radicals derived from the acids HXHX and H (X .X*)respectively. which are strong acids; or

b. the quaternisation of a pyridine derivative of the formula:

3 9 i A .(X) III rir N A fi with a quaternising agent (RALX. wherein A, A,

A, R, R, X and X have the meanings stated above: or

c. for those compounds wherein the linking group A contains one or two amide linkages. the reaction of a mono-carboxylic acid of the formula:

coon. (X

or a reactive derivative thereof. with a suitable monobasic or dibasic compound, or the reaction of an amine of the formula:

wherein A, R, X and n have the meanings stated above, with a suitable monobasic or dibasic compound; or

e. for those compounds wherein the linking group A contains one urea linkage and which are symmetrical, the reaction of an amino compound of the formula V wherein A, R, X and n have the meanings stated above, with a carbonyl compound of the formula (R) .CO, wherein R is a chlorine atom, a lower alkoxy radical or a phenoxy radical; or

f. for those compounds wherein the linking gjroup A contains two urethane linkages, the reaction of an amino compound of the formula V with a suitable bis-chloroformate ester, or the reaction of a chloroformate ester of the formula:

1- (ca- .o.coc1. (x-

/ n VII with a suitable di-isocyanate, or the reaction of an isocyanate of the formula:

((1)9 VIII w TX with a suitable dihydroxy compound wherein A, R.

X and n have the meanings stated above; or

h. for those compounds wherein the linking group A contains one or two olefinic linkages, the reaction of an activated methylpyridinium salt of the formula:

i CH3. GIT

wherein A, R and X have the meanings stated above, with a suitable monoor di-aldehyde;

whereafter if desired a product thus obtained containing an anion (X"), (X) or (X .X) is converted to a corresponding compound containing a different anion (X), (XY or (X.X")"' by basification thereof followed by reaction of the basified product with an acid HX, HX or H (X.X wherein X, X, X and X have the meanings stated above, or by an ion-exchange resin.

The quaternisation process is preferably carried out by heating together the pyridine derivative and quaternising agent, and the inclusion of a solvent, for example nitrobenzene, sulpholane or toluene, is often advantageous in improving the mutual solubilities of the reactants, or to moderate the reaction. The addition of a tertiary amine, for example a hindered tertiary amine such as di-isopropylethylamine is also useful, for removing any acid generated during the reaction.

The process c) to h) for the formation of amide. urea, urethane or olefin linkages may be carried out in generally known manner described in the literature for analogous compounds.

A suitable strong acid HX", HX or H ,(X.X) has a p14,, value of less than 2, and is, for example, hydrochloric, hydrobromic, methanesulphonic, toluene-psulphonic or sulphuric acid.

As stated above, the new compounds of the invention possess valuable antibacterial properties, in that they are effective against a wide range of both Grampositive and Gram-negative organisms, including strains of, for example, Pseudomonads which are resistant to other widely-used antibacterial agents. Further advantages of the preferred compounds of the invention may include, for example, rapid speed of kill, being bactericidal rather than bacteristatic, not being deactivated by hard water, or having more surface activity. Further, textile materials which have been in contact with the compounds of the invention are not stained by treatment with hypochlorite bleach.

Thus, according to a further feature of the invention, there is provided a composition comprising at least one pyridine derivative of the invention together with an inert diluent or carrier.

The composition of the invention may be a pharmaceutical composition, for example in the form of a 102- enge suitable for oral administration, or an ointment, cream, or sterile aqueous or oily solution or suspension for topical use; or it may be a non-pharmaceutical composition, in the form of, for example, a non-sterilised aqueous or oily solution or suspension, or an aerosol, for use as a general, environmental antiseptic or disinfectant, or a mouthwash, paste, gel or fluid suspension non-pharmaceutical compositions are an aqueous solution suitable for use as an antiseptic and containing from 0.02 to 1.0% w/v of a compound of the invention, an aqueous solution in the form of a concentrate containing from 1% w/w to that percentage which gives a saturated solution of a compound of the invention, or powder or tablets for dissolution in water to give an aqueous solution suitable for use as an antiseptic. Preferred compositions for use in dental hygiene are mouthwashes containing between 0.05 and 0.5% w/v (at user dilution) of a compound of the invention; and toothpastes and dental gels containing between 0.05 and 1.0% w/w, preferably between 01 and 0.5% w/w, of a compound of the invention.

The invention is illustrated but not limited by the following Examples:

EXAMPLE 1 General procedure for quaternisation The pyridine derivative (0.01 mole) and the alkylating agent (0.020.1 mole) are heated together, optionally with inclusion ofa solvent, e.g. nitrobenzene to improve the mutual solubilities, or to moderate the reaction, and/or a hindered amine, for example diisopropylethylamine to remove any acid generated during the reaction. The temperature and time of heating are shown for each compound in the Tables, but these are not necessarily optimal conditions and they can usually be varied over wide ranges. The product is crystallised from a suitable solvent and, if required, the anion can be changed by conventional procedures, for example by the use of ion-exchange resins.

suitable for use in dental hygiene for the inhibition of 35 dental plaque formation. l L, The composition may contain conventional excipr- 3 I 1 2 2 ents and carriers, and may be manufactured by the application of conventional techniques. m N ti Preferred pharmaceutical compositions of the inven- 40 1 tion are lozenges, each containing from 0.1 to 1.0% 1 l 2 2 w/w of a new compound of the invention, and preferred A R A R First Second No A=A2 R'=R2 linkage" A linkage" X =X l n-octyl 4 CH CH 4 Ms" 2 n-dccyl 4 CH2CH2 4 Ms 3 ndodccyl 4 CH CH 4 Ms 4 n-octyl 4 (CH. 4 Ms 5 n-decyl 4 (CH2),, 4 Ms 6 n-dodecyl 4 (CH. 4 Ms 7 n-tetra- 4 -(CH 4 Br decyl 8 n-decyl 4 -CH:CH 4 Ms 9 n-undecyl 4 -CH:CH 4 Br 10 n dodecyl 4 CH:CH 4 Ms 1 l CH ,C 3.4-di- 4 CH:CH- 4 C1 NH" Chlorophenyl 12 n-octyl 2 CH:CH 2 Ms 13 n-dccyl 2 CH:CH 2 Ms l4 n-octyl 3 CH:CH- 3 Ms l5 n-decyl 3 CH:CH 3 Ms 1o n-dodecyl 3 -CH:CH 3 Ms I 7 n-octyl 3 -CH:CH 4 Ms I 8 n decyl 3 CH:CH 4 Ms 1) 2-n hexyl- 3 CH:CH 4 Ms oxyethyl 20 4-chloro- 3 CH:CH 4 Cl henzyl 2| 2.4-di- 3 -CH:CH 4 CI chlorohenzyl Z2 Z-naphthyl- 3 CH:CH 4 Br methyl Continued First Second No. A =A R=R'-' linkage A linkage" X '=X'- 23 n-decyl 2 CH:CH 3" Ms 24 n-octyl 3 -NH.CO.NH- 3 Ms 25 n-decyl 3 NH.CO.NH 3 Ms 26 n-decy1 3 NHICO.NH 3 Cl 27 n-decyl 3 NH.CO.CO.NH 3 Ms 28 n-decyl 3 -NH.CO(CH- 3 Ms CQNH- 29 n-octyl 3 NH.CO(CH- i) 3 Ms CO.NH 30 n-decyl 3 NH.CO(CH 3 Ms C(lNH- 31 n-octyl 3 NH.CO(CH- ),t 3 Ms CO.NH- 32 n-decyl 3 NH.CO(CH 3 Ms CO.NH 33 n-decyl 3 CH. ..NH.CO.NHI 3 Br CH.)- 34 n-decy'l 3 CH- ,.NH- 3 Ms .CO(CH- CO.NH.CH 35 n-decyl 3 CH .NH- 3 Ms .CO(CH- CO.NH.Cl-I-; 36 n-octyl 3 NH.CO 3 Ms 37 n-decyl 3 NH.CO 3 Ms 38 n-octyl 3 -NH.CO 4 Ms 39 n-decyl 3 NH.CO 4 Ms 40 n-oetyl 3 CH .NH.CO 3 Ms 41 n-decyl 3 CH- ,.NH.CO 3 Ms 42 n-octyl 2 -CH .NH.CO 3 Ms 43 n-decyl 2 CH NH.CO- 3 Ms 44 n-octyl 3 -CH .NH.CO 4 Ms 45 n-decyl 3 CH .NH.CO 4 Ms 46 n-octyl 2 -CH .NH.CO 4 Ms 47 n-decyl 2 CH .NH.CO 4 Ms 48 n-octyl 4 CO.NH(CH 4 Ms NH.CO- 49 n-decyl 4 CO.NH(CH 4 Ms NH.CO- 50 n-decyl 4 -CO.1 IH(CH 4 Ms NH.CO-

"linkage of left hand pyridine ring to A in the formula as written at the head of the tablet where A is not symmetrical it should be read as from left to right in the formula at the head o1- the table. "linkage of A to right hand pyridine ring in the formula 215 Written :it the head of the table. "Ms=mcthnnesu1phonutet "the methylene group is attached to the pyridine nitrogen atom. and the NH group is attached to R.

Reaction conditions No Temperature Time Additive M.p.(C

1C.) (minutes) (decomposition I 1 I40 I 255 (decomposition) I2 140 60 210-211 13 135 60 189-192 14 I25 20 173-176 15 125 196-198 16 135 30 204-208 17 I30 7 97-99 20 95 5 248-250 21 130 5 224-229 22 130 4 273-276 23 I30 60 228-231 24 140 5 193-1985 25 130 5 233-234 26 195 10 DIE" 2395-244 27 I80 5 nitro- 239-234 benzene Continued Reaction conditions No. Temperature Time Additive M.p.(C.)

(C.) (minutes) 32 I60 5 1095-1105 33 I40 20 nitro- Not crystalline benzene 34 150 I 98-100 35 160 15 131-134 36 15 DIE 157-160 37 30 DIE 168-171 38 I30 30 DIE -152 39 130 30 DIE 166-168 40 140 30 DIE 68-69 41 140 30 DIE 167-169 42 I30 30 DIE 158-160 43 I30 30 DIE 123-125 44 130 30 DIE 167-170 45 130 60 DIE 62-64 46 140 30 DIE 171-174 47 130 30 DIE 89-92 48 30 DIE 167-168 49 30 DIE 174-176 50 160 60 DIE 59-61 "approximate m.p. Com ound \er hygroscopic. 'D1E= di-isopropylethylamine.

Certain of the un-quaternised pyridines, wherein A is an amide containing linkage, used as starting materials for the above compounds are novel, and may be obtained by the following process which exemplifies the preparation of the un-quaternised pyridine starting material for compounds 40 and 41:

Cntinued Starting Material for Mr). (C.) compounds nos.

The unquaternised pyridine starting material for compound 32 is also a novel compound and may be prepared as follows:

3-Aminomethylpyridine (10.8g.) and diphenyl car- S l5 bonate (10.7g.) were mixed, heated together at 140C. for 5 minutes, and the mixture was cooled and stirred for M.p. (C.) with ether. The product was filtered off, washed with fs l fresh ether, and recrystallised from ethyl acetate, m.p.

l30.5-l33.5C. 27 290-292 28 -236-238 EXAMPLE 2 29. 232-235 31.32 161-164 The process described in Example 1 1s repeated, 3? :ggjggg using the appropriate bis-pyridine derivatives and quat- 38, 39 163-166 ernismg agents, to give the following compounds:

3 e l A l (fix- 1 \I @Y G9 A R A 12 No. A =A R =R Fir'st (b) Second 1- 2l llnkage A linkage 1 i 51 -CH c0.- n-octyl 1 -ca .CH 1 01 i 52 CH co.- n-decyl 1 -CH .CH 1 c1 2 2 2 NH- 53 n-nonyl l CH:CH l 1 3:505 CHflCH MS trimethylhexyl 55 n-decyl l -CO.NHNH.CO(CH- 1 Ms comanmco- 56 n-decyl 3 -GO.N( ,N,CO- I 3' Ms 57 -CH CO. n-octyl 3 -CO. 0- Cl 58 -gg co.- n-decyl 3 -CO- .CO- 3 c1 59 -03 c0.- n-dodecyl 3 -co.1\1 fnco- 3 c1 60 n-de cyl 3 -CO.NHNH. CO- 3 Ms 61 n-decyl 3 CO. NH(CH; NH.CO- 3 Ms Continued 1 2 1 2 First (b) Secon 1 2 A linkage A linkage X 9o n-decyl 3 NH. coma; .NH- 3 Ms 91 n-decyl 2 -Nl-I.C0(CH' C0.NH- 2 11$ 92 2-(2 Nil. CO(C11; CO.N11- 5 11s 2 8 butoxy- 013110331)- ethyl 9:) n-deeyl 1 -Ci1 N11.CO(CH' CO. 1 '15 NHEH 2 9 1 n--decy1 j -I l1l .COO(C11 OCO.1'1'11- 3 1 95 rr-docyl '5 N1 1. COO(Cii OCO.N'l-1- 3 MS l 96 n-docyl 'j N'r1.COO(Cl-1' OCO.NF1- 3 11:", 1 9'7 n'decyl 5 -N1-1.COOC1-l C(C, i15bCi1 1 1% 1 000 N11- 98 n-tlecyl 3 -l-I'r1.CO[O(C11 OCO.- 3 Ms 1 NH- 1 i 99 3,5,5" 3 1 Ms. 1 trimethylhexyl 1 (a) linkage 01 left hand pyridine ring to A in the formula as written Continued at the head of the table.

(b) where A" is not symmetrical, it should be read as from left to right in the formula at the head of the table.

(c) linkage of A" to the right hand pyridine ring in the formula as written at the head of the table.

(d) the methylene group is attached to the pyridine nitrogen atom, and the NH group is attached to R.

(e) Ms methanesulphonate.

Reaction conditions No. Temperature Time Additive M.p.( C)

C.) (minutes) 51 110 15 237-239 52 1 261-266 53 140 10 255 54 125 200-250 55 160 30 165-168 56 130 10 212-214 57 120 20 238-2895 58 110 30 toluene 229-231 59 110 30 toluene 224-228 (10 175 5 168-171 61 150 15 122-125 62 160 10 112-1145 63 160 15 128-130 64 195 10 210.5-2125 65 180 15 -98 66 200 2 1 14-1 16 67 140 30 193-194 68 140 150 91-95 69 145 5 202-206 70 140 5 -104 71 150 2 200-2015 72 100 15 250-252 73 15 250-253 74 100 15 258-260 75 180 30 95-98 76 180 20 -113 77 160 10 142-1445 78 150 6(1 sulpholane 2145-2165 79 140 10 154-155 80 10 197-199 81 5 156-159 82 140 5 120-123 83 5 225-228 84 160 2 19615-1975 Reaction conditions "DIE di-isopropylethylaminci A. Certain of the unquaternised pyridines, wherein A is an amide-containing linkage, used as starting materials for the above compounds are novel, and may be obtained from the reaction of an appropriate amine and an appropriate acid chloride by the process described in the latter part of Example 1.

Starting material M.p. (C.) for compounds nos.

Continued Starting material M.p. (C.)

for compounds nos.

Starting material M.p. (C.) 65 l98.5-l99.5 for compounds nos. 75 160-161 5 76 183-l84.5 87/88 l7l.5-l73.5 191-192 89 was-201.5 95 90 158-160 3? {63-169 91 I 8 -l85 93 i 98 142-144 EXAMPLE 3 B. Certaln other of the unquaternised pyridmes, D wherein A is a ureido-containing linkage, used as start- The desfnbefi Example 1 repeated 1 1 ing materials for the preparation of the above the appropriate bis-pyrid ne derivates and quatermsmg pounds of the invention, are novel and may be obtained agents to gwe the following compounds: as follows:

A solution of hexamethylene di-isocyanate (1.68g.) 3 t l v e in toluene (lOmL) was added to a solution of 3- A i 1 2 2 (X .x ammopyridme (1.88g.) in toluene (l8ml.) and the mixture was heated on a steam-bath forv 10 minutes. The a mixture was cooled, and the product was filtered off, 1 1 2 2 washed with toluene and dried, to give l,6-bis[3- A R A R No. A=A R=R First A b Second X=X linkage" linkage" 100 n-decyl 3 NH.COCH' 3 Ms" =CHCO.NH" lOl n-octyl 3 NH.CO(CH OCH 3 Br CO.NH 102 n-decyl 3 NH.COCH OCH CH 3 Br OCHCO.NH 103 n-decyl 3 NH.CO[O(CH 3 Ms OCO.NH 104 n-decyl 3 NH.COO(CH )-,NH- 3 Ms NH 105 n-decyl 2 NH(CH NH 2 Ms 1(16 n-decyl 4 NH(CH NH 4 Br 107 n-decyl 2 NH(CH ,NH 2 Ms 108 n-decyl 3 -O(CH,) 0- 3 Br 109 n-decyl 3 O(CH O 3 Br 1 l0 n-dccyl 3 -O(CH- ,O 3 Br "linkage of left hand pyridine ring to A" in the formula us written ut the heud of the table where A is not symmetrical. it should he rend us from left to right in the t'ormuln at the head of the table.

"linkage of A" to the right hnnd pyridine ringin the tormuln as written at the head of the table. "t indicates a trans double bond. "Ms-= methnnesulphonute.

(pyrid-3-yl)ureido]hexane, m.p. 197199C., the starting material for compound 67.

In a similar manner, using 3-aminomethylpyridine in place of 3-aminopyridine, there was obtained the starting material for compound 68, l,6-bis[3-(pyrid-3-' ylmethyl)ureido]-hexane. m.p. 223225C.

C. Certain other of the unquaternised pyridines, wherein A is a ureidoor urethane-containing linkage, used as starting materials for the preparation of the above compounds of the invention, are novel and may be obtained as follows:

The unquaternised pyridine derivatives used as starting materials in the preparation of compounds and 101 are novel, may be prepared by the process described in the latter part of Example 1, and have melting points of 32l.5322.5C. and ll7-l 19C. respectively.

The unquaternised pyridine derivatives used as starting materials in the preparation of compounds 103 and 104 are novel, may be prepared by the process described at (C) in Example 2, and have melting points of l2l-l23C. and l94l94.5C. respectively.

The unquaternised pyridine derivative used as starting material in the preparation of compound 109 may be obtained as follows:

Sodium hydride (1.32g.) was added portionwise under an atmosphere of nitrogen during 30 minutes. to a stirred solution of 3-hydroxypyridine (2.85g.) in dry dimethylsulphoxide (28ml.) cooled to below 25C. When reaction ceased, 1,6-dibromohexane (3.66g.) was added dropwise with stirring and cooling, and the resulting mixture was stirred a further 3 /2 hours. The mixture was poured into ice-water, and the precipitated product was filtered off and crystallised from petroleum ether (b.p. 6080C.), to give 1,6-bis-pyrid-3- yloxyhexane, m.p. 85C.

In a similar manner, using the appropriate dibromides, there were obtained the butane (m.p. 95C.)

and decane (m.p. 64C.) analogues, the starting materials for compounds 108 and H respectively.

EXAMPLE 4 The methanesulphonate salt, compound 32 (3g) wasv dissolved in water and excess 2N sodium hydroxide was added. A yellow viscous oil separated which was extracted into chloroform. The chloroform layer was washed with water, and then shaken with excess aqueous toluene-p-sulphonic acid. Ether was added to precipitate the toluene-p-sulphonate salt, which was crystallised from a mixture of acetone and acetonitrile, m.p. 127l29C.

The sulphate was prepared in similar manner, m.p. l46l47C.

The acetate (m.p. 87-89C.) was prepared in similar manner, except that the new salt remained in the aqueous phase and was recovered by evaporation of the solvent and crystallisation of the residue from acetone.

EXAMPLE Compositions containing a pyridine derivative of the invention may be prepared from any pyridine derivative of the invention described in the foregoing Exam ples by conventional procedures as illustrated below, where. it is to be understood, the particular pyridine derivative named may be replaced by an equipotent amount of any other pyridine derivative of the invention.

Lozenge A mixture of sucrose (925g), magnesium stearate (lg), gum acacia (3g), water (3ml.) and 3.3- suberamidobis(l-n-decylpyridinium chloride) (0.5g.) is blended and compressed into hard lozenges such that each weighs lg., and contains 5mg. of the antibacterial pyridine derivative.

Antiseptic 3,3'-Suberamidobis(l-n-decylpyridinium methanesulphonate (0.5g) is dissolved in sterile distilled water (99.5ml.) to give a liquid composition suitable for use as an antiseptic.

Toothpaste A solution is prepared by stirring saccharin sodium (0.2g) in purified water (38.8ml.) to which is then added isopropanol (4.0g) and glycerin (g) (Solution I).

A mixture of oil of peppermint (0.6g) and oil of spearmint (0.3g) is added to Pluronic P75 (0.6g. Pluronic is a trade mark) followed by 4,4- glutaramidobis( l-n-decylpyridinium methanesulphonate) (0.5g.) and stirring is continued until a homogeneous solution is formed (Solution II).

Solution 1 is slowly added to Solution 11, with stirring, and Natrosol ZSOHH (lg. Natrosol is a trade mark) is then added, stirring being continued until hydration is complete. A mixture of dicalcium phosphate (20g), Neosyl E.T. (10g), titanium dioxide (lg.) and dried aluminium hydroxide gel (lg.) is then added and mixing is continued until a smooth and uniform paste is formed.

What we claim is:

1. A pyridine derivative of the formula:

wherein R and R which may be the same or different, are each alkyl having 8 to 14 carbon atoms, n-undec- IO-enyl, 2-n-hexyloxyethyl, 2-(Z-butoxyethoxyethyl), 3,4-dichlorophenyl, 4-chlorobenzyl, 2,4- dichlorobenzyl or Z-naphthylmethyl; A and A are each a linking group of the formula CH CONH wherein the methylene is joined to the pyridine nitrogen; (X.X represents two monoanions or a dianion selected from the group consisting of two halide, methanesulphonate, toluene-p-sulphonate or acetate ions or the sulphate dianion; and A is a linking group of the formula:

wherein n is O or 1; m is 0 to l2: and is 0 or i.

2. A pyridine derivative of claim 1 wherein A is a linking group selected from the group consisting of: 

1. A PYRIDINE DERIVATIVE OF THE FORMULA:
 2. A pyridine derivative of claim 1 wherein A3 is a linking group selected from the group consisting of: -NH.CO.NH--NH.COCO.NH--NH.CO.NHCH2--CH2NH.CO.NHCH2--NH.CO(CH2)1-8CO.NH- and -CH2NH.CO(CH2)2-4CO.NHCH2-
 3. The pyridine derivative of claim 1 wherein R1 and R2 are the same and are each n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tetradecyl, n-undec-10-enyl, 2-n-hexyloxyethyl, 2-(2-butoxyethoxy)ethyl, 3,4-dichlorophenyl, 4-chlorobenzyl, 2,4-dichlorobenzyl or 2-naphthylmethyl.
 4. A pyridine derivative as claimed in claim 1, said derivative being 3,3''-ureylenebis(1-n-octylcarbamoylmethylpyridinium chloride).
 5. A pyridine derivative as claimed in claim 1, said derivative being 3,3''-adipamidobis(1-n-decylcarbamoylmethylpyridinium chloride). 